Since the liquid crystal does not emit light itself, thus an external backlight source is needed to achieve displaying in a variety of liquid crystal displays (LCDs), such as LCD devices, LCD televisions. Backlight sources can be divided into two types, i.e., edge type and direct type according to their distribution positions. For an edge-type backlight source, due to its advantages, such as low requirements of the number of light emitting devices, low cost, and thin thickness, it is widely used in LCDs of small and medium size.
FIG. 1 is a partial sectional view of an edge-type backlight module, which includes a back plate 1, a light guide plate 5 and an optical film 7 which are arranged on the back plate 1 sequentially. The module further includes a rubber frame 4 configured to fix the light guide plate 5 and the optical film 7, a light bar 2 arranged close to a lateral side of the light guide plate 5. The light bar 2 includes a plurality of light emitting units 3 arranged thereon. A display panel 6 is arranged above the backlight module. A front frame 8 is also provided for assembling the backlight module and the liquid crystal panel 6. The light guide plate 5 is configured to transmit light from a near end to a far end to make light uniformly emitted from an entire light output surface, so as to form a surface light source for the display panel 6 for displaying.
However, it can be seen from FIG. 1 that, a distance L between the light emitting units 3 and a display region (A region) of the display panel 6 is short. Darker zones where less light illuminates and brighter zones where more light illuminates will be formed between adjacent light emitting units 3, that is, light mixed by the light emitting units 3 is not uniform. Such a phenomenon that brighter and darker zones are alternatively distributed is called a hot-spot phenomenon. In order to eliminate the darker zones, a distance between the light emitting units 3 needs to be reduced. In this way, however, a reduction of the number of the light emitting units 3 is limited, which is not conducive to reduce costs. Further, the space reserved for the light bar 2 is very small, which makes the light bar 2 is difficult to be assembled. The heat dissipation space of the light emitting units 3 is small, which makes heat dissipation be difficult and affects the quality of the module. In addition, a driving circuit board on the light bar 2 has a certain thickness, which is not conductive to make the display module thinner.